Shimano Dura-Ace 7900 [en]

We followed the evolution of the latest Shimano Dura-Ace 7900 groupset since months, but always missed the official information. It’s now over, a few websites have had some
insights… Will it be electronic or mechanic? Made out of alloy or carbon composite? Well, it’s a mix of the four! Indeed, for 2009, Shimano developped two high range groupsets,
introducing a kind of new generation. The first one is a simple evolution of the 7800, while the second one is a complete reworking , it has a battery and a lot of electronic on
board…
Despite the embargos the japanese manufacturer placed: June for the mechanical groupset, and september for the electronic groupset, some websites went ahead and published the informations,
Fiets (dutch magasine) and Competitivecyclist (famous US shop).

Here are the most important features coming along with these two new groupsets:

Shimano Dura-Ace 7900 electronic

The electronic groupset constantly evoluated since its first version spotted early in 2006 on Rabobank and SKIL bikes. You can have a look at the video below to discover or rediscover the
functionnalities of this groupset. Video made by Bicycling magazine.

You can follow the evolutions of this groupset since early 2006 through these articles, in chronological order:

1, 2, "article-6925366.html">3, 4, "article-5779407.html">5, 6, "article-2096810.html">7, 8, "article-2042024.html">9

Shimano Dura-Ace 7900 mechanical

STI levers

- New shapes, more ergonomical
- Under-the-tape derailleurs cable housings
- Bars/lever reach adjustement
- Right lever shift engagement stroke 20% shorter
- Carbon levers
- Titanium hardware
- Not compatible with 7800 derailleurs

Calipers

- Improved geometry, more braking power
- New brake pads, 210% better braking performance under the rain and 120% in the dry
- Titanium hardware

Rear derailleur

- Improved cable pulling system
- Carbon pulley plates
- Compatible with bigger gear range with no triple derailleur required
- Not compatible with 7800 levers

Front derailleur

- The plates geometry and width avoid you from trimming, whatever the gear used
- No unwanted friction of the chain on the plates
- Spring tension is optimized for very smooth chainring shiftings

Crankset

- The carbon crankset seems to be abandonned
- New alloy cranks:
* obviously hollow, the walls thicknesses are reduced from the 7800 version
* Claimed to be the lightest crankset made by a big manufacturer
* Even stiffer than the 7800
- New carbon/alloy bottom bracket for further weight save

Chain

- New design:
* quieter chain
* Power transfer increased of 0.6% if used in combination with the newest 7900 chainrings
* No rubbing with the front derailleur if used with the 7900 chainrings
- Quick Link for super fast assembling and disassembling

Cassette

- Shifting improved
- Lighter cassettes thanks to the alloy cogs carrier
- Wider offers (11-25, 11-27, 11-28 beside the current offers with 7800 Dura-Ace)

Flight Deck comptuter